A common need for SWMM users is to create a time series for a design storm of given depth, duration and return period that follows a particular time pattern distribution. While this feature is available in many commercial H & H software, I couldn't find any freely available tools that do the same for a variety of rainfall distributions. So I wrote Dstorm, a wizard style app for Windows that provides this capability. You can download it from:

https://sites.google.com/view/dstorm .

Dstorm's features include:

- a variety of common rainfall distributions to choose from, such as the Triangular, Huff, SCS, NRCS Regional, Composite, Chicago and Nested distributions as well as a user-supplied custom distribution - automatic adjustment of 24-hour distributions to shorter durations - optional use of Intensity - Duration - Frequency (IDF) data retrieved from the NOAA Atlas 14 database - the ability to copy or save the design storm time series for later use within SWMM - deploying it as an Add-In Tool within SWMM.

I hope the SWMM user community will find the tool useful.

A great add on to SWMM 5 - thanks, Lew

Wow! Thanks Lew!

A note to my US colleagues: while this new tool incorporates the ability to generate a traditional SCS hyetograph, I would encourage you to only use SCS curves when your project absolutely mandates them. They employ grossly out-of-date engineering methods for which we have far better options today, such as the composite (alternating block) method that Lew has incorporated into Dstorm. I wrote an article discussing why SCS curves should be avoided a couple of years ago that was focused on Boston, but comparable findings apply for many other locales - http://files.engineers.org/file/February-2020-BSCES-News-Issue.pdf

i also ;posted this on LinkedIn in the SWMM professional network - here is the link if you want to show Dstorm on LinkedIn as well.

https://www.linkedin.com/feed/update/urn:li:activity:6952289440153186304/

I have a tool for generating UK hyetographs based on the FSR, and FEH99 rainfall models.

Would you be willing to upload your tool for generating UK hyetographs based on the FSR, and FEH99 rainfall models please?

Hi David,

The setup file can be downloaded from...

www.tidc.co.uk/QSRPG_Setup.exe

Thanks Peter. Much appreciated.

Hi Dave,

I would appreciate any feedback.